1. Field of the Invention
The present invention relates to a method and apparatus for localizing a sound image of an input signal to a spatial position, and more particularly, to a method and apparatus by which only important information having influence on sound image localization of a virtual sound source is extracted, and by using the extracted information, a sound image of an input signal is localized to a spatial position with a small number of filter coefficients.
2. Description of the Related Art
When virtual stereo sound (3-dimensional (3D) sound) for localizing a sound source in a 3D space is implemented, a measured head related impulse response (HRIR) is generally used. The measured HRIR is a transfer function relating the eardrums of a listener with respect to the position of a sound source, and includes many physical effects having influence on the hearing characteristic of the listener from when the sound wave is generated by a sound source until it is transferred to the eardrums of the listener. This HRIR is measured with respect to changes in the 3D position of a sound source and changes in frequencies, by using a manikin that is made based on an average structure of a human body, and the measured HRIR is consisted of a database (DB) form. Accordingly, when a virtual stereo sound is actually implemented by using the measured HRIR DB, problems as described below occur.
When a sound image of one virtual sound source is localized to an arbitrary 3D position, a measured HRIR filter is used. In the case of multiple channels, the number of HRIR filters increases as the number of channels increases, and in order to implement accurate localization of a sound image, the coefficient of each filter also increases. This causes a problem in that a large capacity, high performance processor is required for the localization. Also, when a listener moves, a large capacity HRIR DB of HRIRs measured at predicted positions of the listener, and a large capacity, high performance processor capable of performing an interpolation algorithm in real time by using the large capacity HRIR DB are required.